Rotary machine of the alternating piston type



c. BANcRoFT 2,553,954

ROTARY MACHINE oF THE ALTERNATING PIsToN TYPE May 22, 1951 8 Sheets-Sheet l Filed Oct. 22, 1948 www INVENTOR.

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ROTARY MACHINE 0E THE ALTEENATTNG PTsToN TYPE Filed Oct. 22, 1948 8 Sheets-Sheet 3 nini -i frm,

1N VEN TOR. Cf/m 5 @4A/PUF? [www May 22, 1951 c. BANcRoFT 2,553,954

ROTARY MACHINE oF THE ALTERNATTNG PTsToN TYPE Filed oct. 22, 194s s sheets-sheet 4 IN1-"EN TOR.

May 22, 1951 c. BANcRoFT ROTARY MACHINE oF THE ALTERNATTNG PTsToN TYPE 8 Sheets-Sheet 5 Filed Oct` 22, 1948 INVENTOR. ELM/Q55 56m/Waff May 22, 1951 c. BANCROFT ROTARY MACHINE oF THE ALTERNATING PIsToN TYPE 8 Sheets-Sheet 6 Filed Oct, 22, 1948 INI'EA'TOR. @Mags @4A/@Pfiff BY i ,QTTO/P/Vfb/S May 22, 195l c. BANCROFT 2,553,954

ROTARY MACHINE OF' THE ALTERNATING PISTON TYPE Filed Oct. 22, 1948 8 Sheetsheet 7 IN VEN TR. 6AM/Q 5 @AWC/POF? @Trop/V525 May 22, 1951 c. BANcRoFT 2,553,954

ROTARY MACHINE OF THE ALTERNATING PISTON TYPE Filed Oct. 22, 1948 8 Sheets-Sheet 8 INVEN TOR. ff/@Aa 5 @4A/POF? Patented May 22, 1951 ROTARY MACHINE V,OF THE ALT-ERNATING -PIST-ON TYPE Charles Bancroft, New Canaan, Conn.

Application October 22, 1948, Serial Noi-55,893

1-1 Claims.

l This invention relates to rotary piston' ,machines of the type `having a cylinder with closed ends and containing a plurality of rotary pistons radially arranged and rotating about .the

cylinders axis.. The pistons continually revolve in the same direction but alternately withfoscillating velocities, whereby the opposed faces of adjacent pistons define, with the cylinder side and end walls, rotating variable displacement or expanding and contracting chambers. The cylinder may have peripherally spaced ports and the pistons may be timed to separate while passing one port and come together while passing another, whereby the machine may be made potentially useful as a motoror pump.

One of the objects of the present invention is to provide a better -luid sealing between the radial sides oi the .pistons and the .cylinder end walls over which these sides must slide.

Another object is to provide this better sealing by bleeding the fluid from inside the :cylinder and applying it to the outsides of the Vcylinder end walls with 'the latter designed in an improved manner to displace axially of the machine under the force of the pressure of the uid and press against the pistons sides, whereby to reduce or eliminate the need for the pistons sides carrying sealing elements.

Ancillary to these objects is the provision :of a practical arrangement wherein the cylinder end walls rotate with the pistons to reduce the sliding friction therebetween while being axially displaceable and including substantially fluid tight chambers for enclosing the cylinder end walls outsides and to which the fluid may be introduced to develop `adequate or controlled fluid pressure for pressing the end walls inwardly.

Another object is to provide a rotary piston interconnecting and timing power transmission assembly permitting the inner piston ends to be arranged closer to the piston axis and thus permitting the use of shorter pistons with a consequent reduction in the centrifugal stresses and of the inertia and `momentum stresses that must be continually handled during the piston velocity oscillations; that is to say, the outer piston ends may be arranged closer to the piston axis without decreasing the displacement of the machine, and the inner ends can more closely approach this axis. This has the further advantage of providing A`a more Acompact machine without reducing its displacement. A further object is to vconstruct such an assembly so that it may be entirely -located at one end of the cylinder yyet so that the rotary forces .are transmitted through it symmetrically, whereby power can be transmitted between a rotary shaft andthe.

pistons iin a radially balanced manner. This ree` lieves the parts from the eccentrically shifting stresses usually characterizing such mechanisms. when they are locatedsentirely at one end of the 1 cylinder.

Additional objects are to .provide for netterA piston cooling and Working :chamber scavenging, balancing the piston loading .so it is symmetrical respecting the .piston axis, freeing the machine from pressure created axial thrust and, iin eral, to provide a universally useful rotary ma'- chi-ne having all of the forces 'through al1-of lits -more heavily loaded parts symmetrically balanced by being diametr'ically loaded during the machines operation, and with all of fthe par-ts free from engineering complications and avoid-i the described typ .O Ir'llchnfe alla which erna bodies the 'inventions principles and op'e'r'ja This illustrated 'and described 'machine invowes certain design characteristics intended to per. mit the productiono'f a pilot .model 'with as man' as possible or the moving parts made in small machine Shop not equipped with a Shaper, ,and i it is contemplated that design changes might be required .or .desirable in .connection with ymass production .of the machine.

In the drawings the various figures are asf follows:

Fig. 1 is a vertical, ylongitudinal section vof the which work in connection with the piston interconnecting and timing power transmission;

Fig. 7 is similar to Fig. 6 excepting that it shows the opposite sides of the cam sets;

Fig. 8 is a cross section taken from the line 8-8 in Fig. 1 and showing the left hand cam set of Figs. 6 and 7 as it appears in the machine and looking at the side shown by Fig. 7, and

Fig. 9 is a cross section similar to Fig. 2 but showing the machine operating under asymmetrical Working conditions.

In these drawings, similar numerals refer'to similar parts throughout the various figures and the following description has reference to these numbers and figures.

The illustrated machine includes a cylinder end and inner side wall and. rotary piston assembly particularly well illustrated by Fig. 5. This assembly has a tubular rotary shaft I from which a pair of diametric rotary pistons 2 integrally radiate whereby they are relatively immovably xed to the shaft. The shaft I has integral portions 3 projecting beyond both sides of the piston 2. Cylinder end walls 4 and 5 are rotatively and axially slidably journaled by the shaft portions 3 on both sides of the pistons 2 and in sliding contact with both the sides or edges of these pistons 2.

. A pair of diametric rotary pistons 6 are provided for cooperation with the first pair of pistons 2. Both pistons 6 extend integrally from the cylinder end wall 4 whereby their adjacent sides are relatively immovably xed to this end Wall 4. The other sides of these pistons 6 are arranged in sliding contact with the other of the end walls, which is the end wall 5, and the inner ends of the pistons 6 are in sliding contact with the shaft I. Thus the tubular rotary shaft I functions as the cylinder inner side wall, the working space of the cylinder being an annulus.

It follows that when the assembly described above is in the cylinder of a rotary piston machine, uid chambers are defined between the pistons 2 and 6 with the displacement of these chambers variable by relative angular movement between the shaft I and the end wall 4.

Both the end walls 4 and 5 have concentric cylinder outer side walls 4a and 5a respectively projecting outwardly therefrom. The cylinder outer side walls 4a and 5a are illustrated as having inside radii just slightly less than the radii of the pistons 2 and 6. But the radii of the walls 4a and 5a could be smaller. The size depends on the force it is desired to apply to the end walls 4 and 5 to press them inwardly against the pistons sides.

A linear acting piston 'I is relatively immovably fixed to the shaft portion 3 outside of the end wall 4 and in rotative and axially sliding peripheral contact with the inside of the cylinder outer side wall 4a. A similar linear acting piston 8 is immovably iixed to the other of the shaft portions 3 outside of the end wall 5 and in similar sliding peripheral contact with the inside of the cylinder outer side wall a. In both instances these pistons are fixed to the shaft portion 3 by having the pistons provided with openings 9 which fit snugly over the shaft portions 3 and by having the walls of the openings 9 and the shaft portions 3 respectively provided with screw hole halves I0 into which machine screws II may be screwed tightly to join the parts. Only the halves on the shaft portions 3 are threaded, whereby to permit tightening of the parts. In addition, the shaft por- 4 tions 3 and the walls of the openings 9 may be provided with key Ways I2 in which keys I3 are placed. These features permit assembly and disassembly of the parts while making the pistons 'I and 8 practically integral parts of the tubular shaft I and its projecting portions 3, when the screws II are applied with the keys I3 in place.

When the described assembly is in operation in the cylinder of a rotary piston machine and while handling compressed fluid between the rotary pistons 2 and 6, the resulting pressure causes leakage from between the pistons along the shaft portions 3 and up into the spaces I4 (see Fig. l) between the outsides of the cylinder end walls 4 and 5 and the inside ends of the iixed linear acting pistons 'l and 8. As the pressure builds up in the spaces I4 it causes inward displacement of the end walls so they press against the sides of the rotary pistons working therebetween. That is to say the pistons I and 8 function as xed pistons against which the fluid pressure reacts to urge the end Walls 4 and 5 inwardly by their axially sliding on the shaft end portions 3. The drawings are on such a scale that clearance does not show, but just a little play room is needed because the end wall axial movement is slight. Since the fluid passages between the insides of the end walls, and their outsides and the inside ends of the linear acting pistons, formed by the leakage paths around the shaft portions 3, connect with both working sides of all the rotary pistons in the rotary piston cylinder, the pressure in the spaces I4 represents an average of the pressure between the various rotary pistons. Therefore, by proper selection of the reaction piston areas the fluid pressure forces on the piston end walls 4 and 5 may be nicely balanced so as to perform the described sealing function without development of excessive pressure, under normal operating conditions.

As is illustrated, the cylinder end and inner side Wall and rotary piston assembly further includes a third pair of diametric rotary pistons I5 for cooperating with the first and second piston pairs. In this instance the pistons I5 extend integrally from the cylinder end wall 5, which is the one opposite the end wall 4 to which the piston pair 6 is relatively immovably xed. In this instance the pistons I5 are relatively irnmovably xed respecting the end wall 5 due to having their adjacent sides integral parts thereof. The free sides of these pistons I5 work in sliding contact with the end wall 4 with the displacement of the latter under the fluid stress providing good sealing, as previously described in connection with the other pistons.

A second rotary tubular shaft I6 is fitted rotatively inside the tubular shaft I, and it has integral portions I'I projecting beyond both end portions 3 of the tubular shaft I. An outer end plate I8 is xed relatively immovably with the cylinder outer side wall 4a. The drawing shows this done by providing the outer end plate I8 with a cylindrical Iiange I9 that is applied in screw threaded engagement to the outside of the cylinder cuter side wall 4u of the rotary piston cylinder end wall 4. Key pins may be applied to prevent unscrewing when in operation, these pins passing through holes and into key ways I9a. This outer end plate I8 extends radially inwardly outside of the linear acting piston 'I and is immovably fixed to the adjacent end of the second shaft portions I'I. This is illustrated (see Figs. 1 and 5a as being `dese by providing the end plate I8 with a hubl 20, the outside of which is slightly tapered and onto which a nut 2l is screw threaded so that when tightened it compresses this hub 20. The inside of the latter and the outside of the adjacent por--Y tion I'I of the second tubular shaft I8 are shown provided with key ways 22 in which keys 23 are tted. Thus when the nut 2l is tightened the outer end wall I8 becomes in effect an integr'al part of the projecting portion of the shaft I5 at Vthat end 'of the assembly. However, the shaft I6 may shift or move axially as required lto permit displacement of the end wall AI8 in the ner described. Space may be initially provided for this action or wearing ofthe parts may cause it, the parts being tted with the usual tolerances initially;

The assembly includes a seeondouter-end plate 24 that is rotatively f-ree from the second shaft I6 but which also has a cylindrical flange 25 that is in screw threaded engagementwith the outside of the cylinder outer side wall 5a of the rotary piston cylinder end wall 5, whereby the end plate 24 and the end wall 5 are rotatively interconnected. Key pins are also used here, the holes and key ways being shown `at 25al and one of the pins at 25o. In this instance also the outer end plate 24 is free to move axially with 'the end wall 5 so as not to interfere with the latter-s described sealing movement.

The assembly described has the advantage that rotation of the linear acting piston Bat the right hand end of the assembly, controls the rotation of the rotary pistons 2, while `rota-tion of the right hand end portion of the -second tubular shaft I6 controls the rotation of the pistons 6, and rotation lof the right hand end plate 24 controls the rotation of the pistons I5. In other words all three pairs of pistons may be individually rota tively controlled from, one end of the assembly, which is the right -hand end in the illustrating drawings. At the same time the diameter` of the `tubular shaft I may be kept relatively small, this in turn permitting the use or pistons of relatively short radii while permitting the machine to have a relatively large displacement. This -is of advantage in producing a compact machine and also because it reduces the centrifugal stresses and the stress of momentum and inertia which must be handled by any rotary alternating' pistonmac-hine.

The linear acting pistons 'I and 8 are referred to las pistons but ythey may also be termed reaction equalizing ilywheels. As previously ded scribed, they work in the cylinders provided by vthe lparts 4a and 5a in the manner of xed linear acting pistons, but these parts are `shown as being -inade heavy to function also as 4flywheels for the rotary piston pair 2 to balance ltheir vrotary momentum and inertia forces respecting :the other vpiston pairs which are -xed to the cylinder end Walls so the 'assemblies are -by themselves heavier than the piston assembly 2 which has only the tubular shaft l to increase its rotary inertia and momentum forces. The end walls 4 and 5, the cylindrical parts 4a and I9, and Scand 25, together with the end plates I8 and 24, provide the rotary 'pistons '6 and I5 with flywheel eiects which are thus equalled by the shaft and pistons 2 having the ywheels 'I and 8.

In some instances there is the 'possibility that the assemblies might develop Vexcessive Huid pressures in the spaces I4 between the linear walls 4 and 5. This .might occur if the piston areas are too great. An excessive pressure is consideredas one in excess of that required for' adequate iluid sealing, such excessive pressure being undesirable because of the additional friction and wear it introduces.

The above trouble is avoided by providing the linear actingy pistons 1 and 8 with transverse passages 26 which are closed `by ball valves 21 under the pressure of compression coil springs 28. VThe arrangement is such that for fluid to leak and escape from the spaces I4 through the passages o'r bores y2li it must overcome the forces of the compression springs 28. These compres-y sion springs 28 are in turn adjusted to maintain just enough pressure in the spaces I4 to displace or inwardly press therotary cylinder end walls just 'sufficiently to accomplish the sealing functions previously described. As soon as the pr`e`s= sures exceed rthis amount they bleed oir through the pressure responsive valves provided by the balls and springs described. With this arrangement, constant sealing pressures of predetermined values may be maintained between the inwardly displaceable rotary cylinder end walls and the sides of the rotary pistons that must slide on theseend walls.

It may now be appreciated that the described assembly broadly features, in effect, the sub combination of a rotary shaft, as exemplified by the shaft I, a rigid disk relatively immovably xed 'to this shaft, as exemplified by either of the pistons 'I or 8, and a vane relatively immovably `iixed on the shaft, as exempliiied by either of the pistons 2, and which is spaced axially thereof from the disk. Thus the disk and vane rotate with vthe shaft. The subcombination further `features an axially displaceable diaphragm,A

in the Iform of either of the rotary piston end walls 4 or 5, surrounding the shaft between the disk and vane and in sliding contact with the adjacent radial sides -of the latter and rotatively independent respecting the shaft and disk and vane.V Therefore, with an enclosure for the ad jacent sides of the disk and diaphragm, as exemplified by `the cylinder outer Walls 4d and 5a, and which permits relative rotation of the disk and diaphragm, it becomes possible by providi-'ng a source of fluid under pressure 'and a passage between this source and the adjacent sides of the disk and diaphragm, to provide the effect of stressing the diaphragm with uid pressure so it displaces vand presses against the adjacent radial 'side of the vane. The valved vent opening, 'as exempled by the passages 26 and the ball valve 21 with its compression spring 28, provide 4for venting between the adjacent faces of the disk and diaphragm and thus con-- trolling the diaphragm displacement.

'The described cylinder end and inner side wall and 'rotary piston assembly provide for controlling all of the piston movements from one end of the assembly, as vpreviously noted. At this end an improved rotary piston interconnecting and timing power transmission assembly is provided as described below.

The linear acting piston 'or iiywheel B, which is the right hand one in the drawings, functions i-n effect to provide diametric crank arms for the -pair of rotary pistons 2, and from which vextend i'a Vpair of diametric crank pins 29 and 3I. The J'right hand end of the second tubular vshaft I6 provides diametric crank arms I6a from which a pair of diametric crank pins 32 and 3i3 extend. These crank pins -32 and l83 are located respecting the crank pins 29 and 3l so that the two pairs of crank pins revolve concentrically in the same radial plane and orbit. The crank pins 32 and 33 serve to control the rotation of the rotary pistons 5. Finally, the outer cylinder end plate 24 functions in effect to provide diametric crank arms from which a pair of diametric crank pins 34 and 35 extend, these crank pins being located to be in the same radial plane and orbit as the crank pins 29 and 3l. A clearance hole 38 is formed in the end wall 24 so the pins 29 and 3l may project through it. Thus there are three pairs of crank pins with one pair provided for each of the rotary piston pairs.

It is to be noted that each of the pairs of diametric rotary piston cranks respectively provide short and long crank pins. Thus the crank pins 29, 32 and 34 are shorter than the crank pins 3|, 33 and 35. Therefore, the short and long crank pins respectively revolve in axially spaced parallel radial planes.

Timing control of the various piston crankpin pairs is effected by mechanism including two sets of two laterally offset parallel circular plate cams probably best shown by Figs. 6 and 7. The left hand set in these figures comprises the two eccentric circular plate cams 31 and 33 and the right hand set comprises the two eccentric circular plate cams 39 and 49. In each set the plate cams are relatively immovably xed together with a common axial rotary bearing interposed between and in line with the respectively laterally ofset axes of the plate cams. Thus the cams 31 and 38 have the common axial rotary bearing 4l while the cams 39 and 4i) have the common axial rotary bearing 42. All the cams are eccentric respecting their common axial bearings.

As shown by Fig. 1, the second tubular shaft I6 is journaled-by bearing surfaces 43 on a solid crankshaft 44, so the latter is concentric with the various piston cranks provided by the parts of the previously described inner side wall and rotary piston assembly, and the various crankpins. This crankshaft extends well beyond both sides of this assembly, and on its right hand 1side A adjacent the orbits of the various piston crankpins, this crankshaft has axially spaced diametric cranks 45 providing diametric axially spaced crankpins 45 and 41. In other words, the crankshaft provides a double throw crank mounting diametric crankpins.

The crankpin 48 revolves at least adjacent and concentric to the radial plane through which revolve the shorter ones of the various piston crankpins 29, 32 and 34. The other crankshaft crankpin 41 revolves adjacent and concentric to the other radial plane in which the longer piston crankpins revolve, namely, the crankpins 3|, 33 and 35. These crankshaft crankpins respectively journal the cam sets of Figs. 6 and '1 by their common axes. The crankpin 45 journals the left hand plate cam set 31 and 38 by its rotary bearing 4l, and the crankpin 41 journals the right hand set plate cam set 39 and 49 by its common bearing 42. It follows that each cam set is mounted with each 'of its plate cams rotating eccentric the crankshaft crankpin on which they are journaled as a set.

A set of laterally spaced parallel linear cam bearings diametrically engage peripherally each of the plate cams. These cam bearing sets are arranged respectively at right angles to each other Where engaging the plate cams of each set of the latter. Thus, as shown by Figs. 1, 4 and 8, the parallel linear cambearings 48 which engage the periphery of the plate cam 31 may be horlzontal, and the linear cam bearing set 49 which engages the plate cam 38 maybe vertical. Also the linear cam bearing set 5i) mat7 be vertical While the cam bearing set 5l may be horizontal, these respectively engaging the plate cams 39 and 40. k

Note that the cams 31 and 38 directly Work against the linear cam bearings provided for them, but that the plate cams 39 and 49 revolve in crossheads 39a and 40a, with the latter guided by the sets of parallel linear cam bearings. The crossheads are similar and one of them 39a is illustrated -by Fig. 4a as being made in conventional crosshead fashion. These crossheads are considered desirable in that they reduce or eliminate chattering at these points. Such an arrangement may also be used in the case of the plate cams 31 and 38. The mechanical motion is the same in either instance, but the crossheads may provide for smoother operation, particularly when used where shown.

With the above mechanism, rotation of the crankshaft 44 effects relatively opposite, cammed eccentric rotation of the various plate cam sets with concentric revolution of these cam sets about the axis of the crankshaft 44. This same motion is effected if one of the plate cams in each of the plate cam sets were eliminated, but in that event it becomes possible for the assembly to lock against further rotation. That is to say, it becomes possible to reach dead center positions. If the machine is used under conditions providing sufcient momentum to coast the parts past such dead center positions this difficulty might not be too important. However, it is completely avoided by the use of the two sets of double plate cams in conjunction with the right angularly arranged sets 0f linear cam bearings. This follows because when one of the plate cams is at its dead center position, the other of the plate cams of that set is not and is receiving moving force. Therefore, it is impossible for Athe plate cam sets of the present invention to ever lock due to any one plate cam occupying a dead center position.

Each of the piston cranks crankpins is journaled in a crosshead. In each instance where it shows, the crosshead is numeraled the same as the pin for which it is provided with the numeral followed by an identifying a. This use of crossheads, also, is in the interest of smoother operation.

The left hand ones of the cams of each of the plate cam sets, mount linear bearings for above crossheads, and these bearings radiate from the cam sets common axial bearings. As shown by Fig. 6, the plate cam 31 mounts the three linear bearings 52 by having them formed directly in its face that is relatively adjacent the shorter piston crankpins, namely, 29, 32 and 34. But since the ca-m 39 of the other or right hand cam set is too small in diameter, in this instance the three linear bearings 52a are formed in a circular plate 53 that is carried by the face of the plate cam 39 that is relatively adjacent the longer of the piston crankpins, namely, 3l, 33 and 35. The left hand plate cam set has clearance holes 54 through which the longer crankpins project to the other or right hand plate cam 1 so that the crossheads on the longer pins may properly Work in the linear bearings 52a. One of these clearance holes interrupts the circular periphery of the cam 31 but the gap is adequately spanned by the cams linear bearings,-

so the cam functions as a circular eccentric cam.

Now it is apparent that the various piston cranks through their crank pins and the parts described above are interconnected for rotation at mutually Varying velocities with constant velocity rotation of the crankshaft 44. Furthermore, there is a substantially symmetrical force distribution throughout, whereby the described rotary piston interconnecting and timing power transmission assembly carries all of the working stresses in a nicely balanced manner. This follows from the fact that each piston pair works through diametric cranks and diametric piston pins with the latter working through the eccentric plate cams with the necessary reaction to the latter provided by the various sets of parallel linear cam bearings.

'Ihe right hand cam set is provided with a planet gear 55 which is fixed to the eccentric cam 40 concentric the arial bearing 42. By supporting the' right hand end of the crankshaft 44 in a bearing 56 concentrically formed in the end of a power transmission shaft l with the latter connected with an inwardly facing concentric ring gear 58 arranged to continually mesh with the pinion 55, it becomes possible to transmit power to and from the machine otherwise than through the crank shaft 44. This ring gear 53 may be provided in a form spanning the throw of the farthest right hand one of the cranks 45 and should have a diameter permitting it to be constantly in mesh with the planet pinion 55 as the latter travels through its orbit on the crankpin lil' of the crankshaft 44. This arrangement reduces friction and stresses on the crankshaft 44 and also provides a reduction gear drive.

The Various eccentric plate cams revolve and rotate at uniform speeds with uniform speed of the crankshaft 44. The necessary piston acceleration and deceleration is obtained through the coaction of the linear bearings 52 and 52a with the various piston crankpins.

It should be noted that the drive between the planet gear 55 and the ring gear 58 involves rotative forces only, the radial pressures required for the cam action of the adjacent cam set, being provided entirely by the set of linear cam bearings previously described. The cam sets and linear bearing may be made large to adequately meet all power transmission needs.

The cylinder end and inner side wall and rotary piston assembly previously described, is shown working in a cylinder block 55| which provides the cylinder side wall 6i! required to complete the confinement of the variable displacement fluid spaces between the various rotary pistons. The cylinder block 59 may be cored to provide liquid. cooling spaces 6 I.

A transmission case 62 may be used to house the rotary piston interconnecting and timing transmission assembly previously described, the cylinder block 59 being shown with a generally cylindrical contour having open ends with the right hand end closed by this transmission casing 62 and its left hand end closed by a cap 53. In all instances the parts may be fastened together by the use of finished surfaces, gaskets if necessary, machine screw elements and the like.

The end cap 63 provides a journal bearing 63a for the left hand end of the crankshaft 44. Ball bearings @3b journal the drive shaft 5l and through it the other end of the crankshaft 44, at the -other end of the machine.` The outer end plates I8 and 24 are shown respectively provided with outwardly projecting annuli I6a and 24a providing peripheral sealing rings respectively working against a cylindrical sealing surface 6d in the end cap 63 and against a similar cylindrical surface 65 formed in an insert 66 positioned in the cylinder block 5t and the'transmission casing 62.

Due to the inherent characteristics of the machine, the cylinder block 59, transmission case 52 and end cap G3 may all be made With a generally cylindrical or circular cross section. With the inside of the transmission case 62 generally cylindrical, the insert 66 may be circular, like a plate, and comprise one of a plurality of circular plates, the others of which provide the various sets of parallel linear cam bearings previously mentioned. Thus the linear cam bearings 4S may be formed in a circular plate 48a, and the linear'cam bearing set 49 may be formed in a similar circular plate 49a, with the other set of linear bearings 5U and 5i respectively formed in similar circular plates 50c and 5Ia. A spacer plate 61 may be used to take up the space required by the plate 53 providing for the linear crosshead bearing 52 in the case of the right hand cam set. All of these plates may be provided with a plurality of holes 58 which line up when the plates are stacked in their proper angular relationship and through which bolts or rods may be passed to anchor them against rotation. The plates providing the sets of parallel linear cam bearings must be firmly anchored since they carry the reaction required to rotate the eccentric plate cams. Should any 'of the plates function as dams which might prevent drainage of the transmission case 62, which will normally be partially filled with oil, drainage holes may be used where necessary. One such hole is illustrated at 69 in Fig. l.

Fluid pressure vented or bled through the passages 26 in the previously described linear acting pistons, might produce an unbalanced condition in some instances. Thus in the case of the piston 'I the vented fluid cannot escape except through the sealed cap 63 which is deliberately designed to reduce fluid leakage. But leakage venting through the valved passage of the piston 8 may nd its way to the transmission case 62 which not only provides a larger volume but which might be itself vented to the atmosphere in accordance with standard practices in connection with transmissions generally. Under such conditions a pressure might develop inside of the end cap 63 which would not be balanced by a corresponding pressure on the opposite side, whereby there would be a tendency to thrust the machines parts to the right. Any such trouble may be avoided by providing the end wall I8 with a passageway 'I0 having a short leakage path to the outlet of the valved vent in the piston 1, and by providing the end cap B3 with an opening 'II through which the uid pressure may escape. This arrangement alone will work all right if the transmission case 62 is also vented to the atmosphere. However, it may be desirable to completely seal the transmission casing 62 from the atmosphere. In that event an oppositely unbalanced condition might be obtained, but this trouble can be avoided'by providing the transmission casing 62 with kan opening 'I2 and connecting a pipe I3 withVV this opening 'I2 and the opening 1I-in the casing end 63. With this arrangement a completely: vbal'- anced condition may be maintained at all times without any venting to the atmosphere. YThe hole 'I2 in the transmission case is normally necessary anyway to provide for draining lubricant from the casing. Although not shown, the casing normally will be provided with another and higher hole with a suitable closure therefor and through which a lubricating oil may be applied to the casing.

Although not disclosed, it is to be understood that the cylinder block 59 and transmission case 62 should be adapted for connection to a suitable supporting base or machine mounting of some sort to provide for positioning the machine.

Although not previously mentioned, all ends of the rotary pistons which must work against the cylinder side in sliding contact therewith may be provided with sealing bars 'f4 arranged generally in the manner of piston rings in ordinary reciprocating piston machines. That is to say, the piston ends may be slotted to receive the sealing bars and spring elements may be used to urge the bars outwardly. No piston side edge sealing arrangement is needed because of the previously described features.

The cylinder block 59 is cored out to provide diametric intake passages 15, and diametric exhaust passages 16 with the latter leading to ports 11 positioned centrally of the length of the cylinder 60 with the intake passages 15 straddling the exhaust passages 16 and leading to ports 1S that straddle the exhaust ports TI. The exhaust ports Tl should slightly lead the intake ports 'i8 respecting the rotating direction of the various rotary pistons. Fig. 2 shows one pair of rotary pistons just clearing the exhaust ports, while Fig. 3 shows both the intake and exhaust ports open during scavenging of fluid from between the pistons.

Figs. 2 and 3 show the machine set up as an internal combustion engine and provided with appropriately positioned, diametric, solid fuel injection nozzle 19 and diametric combustion domes 80 which are provided with detonating spark plugs 8l and appropriately positioned so that the firing occurs, with proper timing, at the proper time. That is tofsay, as any leading piston clears any exhaust port, the burnt gases may exhaust through the passages 16 and thereafter the intake ports 18 are cleared by the piston.

To charge the machine with air for another firing cycle, it is necessary to use a scavenging blower, and such is illustrated at 82 as being driven by the crankshaft 44 of the machine. With the outlet of the blower 82 connected to the in take passages T by conduits, not shown, it becomes possible to thoroughly scavenge the spaces between the pistons after any leading piston has cleared both the exhaust and intake ports. The initial high pressure is first released through the exhaust port and thereafter the intake port is opened. This scavenging has the advantage that it also provides for cooling the working faces of the various pistons during the scavenging cycle. Since the intake passages straddle the exhaust passages, as they respectively go to and from the intake and exhaust ports, thorough cooling of the exhaust passages is also obtained at this time. As any trailing piston closes the exhaust port there is an interval when the intake port remains open so that the blower 82 may function as a super-charger due to the ramming effect thus made possible. Thereafter the pistons come together and compress the air While the solid fuel is injected through one or the other of the nozzles '19.` After this the pistons may actually contact 'so as to vforce the now highly compressed charge up into one or the other of the combustion domes 88. Then when firing occurs the expanding gases are available to thrust the pistons apart.

The foregoing action may occur diametrically in the manner illustrated by Figs. 2 and 3 so as to obtain a complete balancing of the forces involved. Alternately, it may occur on only one side of the motor with the other side then functioning as a pump by an arrangement of suitable ports as required for intake and exhaust. The described features are of course not required when the machine is Working as a pump. It is to be understood that all fluid displacement machines of the type involved by this invention may be used to function either as a 'motor or pump by slight modifications.

In the modification shown by Fig. 9, only a single intake port 18a is used, and the machine is provided with a carburetor, not shown, for mixing the solid fuel with the air. The pistons are timed to be separating as they traverse this port 18a whereby they suck in a charge. Thereafter they compress the charge into the detonating chamber 80a provided with a spark plug 8Ia which then res with consequent driving of the pistons apart until the leading piston in each instance clears a single large exhaust port 11a of great circumferential extent. Thereafter, as each leading piston clears a fluid pressure input port 83 scavenging is obtained with the consequent cooling effect, and after the trailing pistons close the port 83 full exhaust follows. Here again, the pressure input port 83 may be connected with passages 33a which straddle the exhaust passage which is in this instance the port 'Ha itself, whereby to get the cooling advantages previously explained. It is to be understood that the entrance to the passage 83 should be connected to the blower 82 for this cooling and scavenging effect. This modication serves to show the advantages of the invention when diametric firing or compression is not involved and also to show that the cooling and scavenging may be separate from the intake.

Another possible modification is the use of annular spring elements I4a in the spaces I4 and which are illustrated in Fig. l. These spring elements may take various forms but should be designed to function as compression springs working axially in the spaces I4 for continuously thrusting or pushing the cylinder end walls inwardly against the rotary pistons sides. The linear acting pistons function to take the reactions of these spring elements with the stress transmitted oppositely through the shaft carrying these linear acting pistons so as to cancel out by opposite reactions. These spring elements might be used alone to provide the cylinder end wall pressure in which case theV valves in the passages 26 of the pistons 1 and 8 might be removed. That is to say, uid pressure would not be relied upon. The spring elements may be used in combination with the fluid pressure should this prove desirable, or the spring elements may be eliminated and fluid pressure relied upon alone.

This application is a continuation-in-part of applicants copending applications bearing Serial No. 572,611 led January 13, 1945, and bearing Serial No. 743,517 led April 24, 1947, now respectively, Patents No. 2,444,480 and 2,444,481, issued on March 6, 1951.

I claim:

1. A cylinder end and inner side wall and ro tary piston assembly for a rotary piston machines almanac Vcylinder and con'iprising,l in combination', a tubular rotary shaft, at' leastl one rotary piston with. its inner end relatively immovably fixed' to 'said shaft, the latter having portions projecting vpiston and with one of. itsV sides relatively immovably fixed to the one of' said end walls and its other side in sliding con-tact with the other of said end walls and its inner end in sliding contact with said shaft, the latter functioning as the cylinder inner side wall, whereby when said assembly is inV said machines cylinder at least one fluid chamber is defined between said pistons with its displacement variable by relative angulal1 movement between said shaft and said end wall fixed to said second piston, said end walls having concentric cylinder outer side walls projecting outwardly therefrom, and linear acting pistons relatively immovably xed to' said shaft portions outside of said end walls and in sliding peripheral vcontact with the insides of said cylinder outer side walls, and fluid passages between the insides of said end` walls and their outsides and the insideends of' said linear acting pistons, whereby operation of said assembly in said machines cylinder vand while handling compressed iiuid between said rotary pistons, results in said compressed fluid entering between said end wall outsides and said reciprocating piston inside ends and tending to cause inward displacement of said end walls with said linear acting pistons having their resulting displacement forces cancelled by opposite transmission in tension through said tubular shaft.

2. An assembly as defined by claim 1 and which further comprises in combination therewith, at least a third rotary piston for cooperating with said rst and second pistons and with its adjacent side relatively immovably fixed to the other of said end walls opposite that to which said second piston is relatively immovably xed and with the other side of said third piston in sliding contact with the just named other end wall, a second rotary shaft fitted rotatively inside said tubular shaft and having portions projecting beyond both said tubular shafts ends, and outer end plates for and fixed relatively immovably with Said cylinder` outer side walls and radially extending inwardly outside of said reciprocating pistons with one of said end plates relatively immovably xed to one of said second shaft portions, said second shaft being axially movable, and the other rotatively free from said second shaft, whereby relative angular movement of said cylinder end walls and said rotary pistons may be transmitted entirely to and from the one end of said assembly where said outer end wall is rotatively free from said shaft.

3. An assembly as defined by claim 1 and which further comprises, in combination therewith, passages having controlling valves and venting the insides of said linear acting pistons, whereby to control the pressure of said fluid between said cylinder end wall outsides and said linear acting piston insides.

4. A subcombination including a rotary shaft, a rigid disk relatively immovably fixed on said shaft, a vane relatively immovably fixed on said shaft and spaced axially thereof from said disk whereby said disk and vane rotate with said shaft, an axially displaceable diaphragm surrounding said. shaft between said.' disk' andvane and' in slidingy contact with the adjacent radial side of the latter and rotatively independent respecting said shaft and disk and vane, an enclosure for the adjacent sides of said disk and said diaphragm and permitting their relative rotation, a source of fluid under pressure, and a passage between said source and the adjacent sides of said disk and diaphragm.

5i. A subcombination as dened by claim 4 wit said disk having a valved vent opening from between the adjacent faces of said disk and diaphragm.

v 6. A rotary piston interconnecting and timing power transmission assembly for a rotary, alternating piston machine and comprising in cornbination, a plurality of concentric rotary piston cranks providing a plurality of crank-pins revolving concentrically in a common radial plane, a set of twov laterally offset parallel circular plate cams relatively immovably fixed together with va common axial rotary bearing between andy in line with their respective axes, a control crank rotating concentric said piston cranks and j providing a crankpin revolving concentrically with their crankpins in a radial plane at least adjacent their common radial plane, said control cranks crankpin being journaled in said cams common axial bearingr and thus mounting them to rotate eccentric said crankpins, a set of parallel linear cam bearings diametrically engaging peripherally each of said cams with said bearing sets at right angles to each other, whereby rotation of said control crank with relatively opposite cammed eccentric rotation and concentric revolution of said cam set is effected, the one of said cams relatively adjacent said piston cranks crankpins mounting linear bearings for said piston cranks crankpins and which radiate from said cam sets common rotary bearing, whereby said piston cranks are interconnected for rotation at mutually oscillating velocities with constant velocity rotation of said control crank.

7. An assembly as defined by claim 6 and further including, in combination, a rotary power transmission shaft and gearing interconnecting said revolving cam set therewith, whereby power is transmitted between said piston cranks and said shaft through said cam set.

8. A rotary piston interconnecting and timing power transmission assembly for a rotary piston machine and comprising, in combination, a plurality of pairs of diametric rotary piston cranks with each pair respectively providing short and long crankpins with said piston cranks concentric and with said short and long crankpins respectively revolving in axially spaced parallel radial planes, two sets of two laterally offset parallel circular plate cams which in each set are relatively immovably fixed together with a common axial rotary bearing between and in line with their respective axes, a crankshaft concentric said piston cranks and having diametric cranks providing diametric axially spaced crankpins with one revolving at least adjacent and concentric to one of said radial planes and the other revolving adjacent and concentric the other of said planes, said crankshafts crankpins respectively journaling said cam sets by their said common axial rotary bearings and thus mounting them to rotate eccentric said crankpins, a set of parallel linear cam bearings diametrically engaging peripherally each of said cams with said cam bearing sets respectively at right angles to each other where engaging the plate cams of each set of the latter, whereby rotation of said crank shaft with relative opposite cammed eccentric rotation and concentric revolution of said cam sets is eected, the one of said cams of each of said cam sets that is relatively adjacent said piston cranks crankpins mounting linear bearings for said piston cranks crankpins and which radiate from said cam sets common axial bearings, said short crankpins working in the linear bearing of the relatively adjacent cam set and the latter having clearance holes through which said long crank pins Aproject to the other of said cam sets, whereby said cranks are interconnected for rotation at mutually oscillating velocities with constant velocity rotation of said crank shaft and with a symmetrical force distribution.

9. An assembly as dened by claim 8 and further including, in combination, a rotary power transmission shaft and gearing interconnecting at least one of said cam sets therewith, Whereby power is transmitted between said piston cranks and said transmission shaft through said cam sets.

10. A rotary piston machine including the combination of a piston and cylinder end wall assembly adapted to bleed fluid under pressure from between the cylinders to outside of the end walls thereof, a piston interconnecting and timing transmission at one end of said assembly, a

16 cylinder block providing a cylinder for said assembly, a transmission case for said transmission and enclosing that end of said assembly, a cover enclosing the other end of said assembly and a uid conduit interconnecting the insides of said cover and .said transmission, whereby unequal pressure build-up at either end of said assembly is prevented.

11. A rotary piston machine assembly comprising rotary pistons mounted to rotate about an axial shaft and having piston cylinder end Walls that are free to move at least slightly axially of said shaft with the latter carrying relatively rigid walls for enclosing the outsides of said end walls and with provision made for at least restricted interconnection between all the mutually opposed faces of said walls.

CHARLES BAN CROFT.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,482,628 Bullington Feb. 5, 1924 1,497,481 Bullington June 10, 1924 2,048,825 Smelzer July 28, 1936 2,061,049 Spellman Nov. 1'7, 1936 2,312,891 Ferris Mar. 2, 1943 

